Darksiders
So for Christmas my cousin got me an Xbox 360, and I've been catching up on the various games that I've missed out on the first time around. Darksiders is something I never thought I'd be into, but I wanted to take a chance on a large form game like this and man am I glad I did. I takes the combat and gore of the God of War games and combines them with dungeon style puzzle solving a la Legend of Zelda. The combat feels great and the game is challenging enough to not feel like a chore but not so much that it seems annoying impossible.
Also, have been playing these
Fez
This is the first game I bought for Xbox Live and was one of the main reasons I wanted a 360. At first this seems like a cute 2d platformer with a mechanic that makes a 2d/3d world in order to solve puzzles, but once you really start to explore it there's SO much more to it that you may not even realize. I'm not going to spoil anything, but I highly recommend that you try and explore everything in the game to get the full experience.
Skate 3
Let me say right now that I have been a massive fan of the Tony Hawk pro skater games since buying the third installment for my Gamecube when I was a kid. Still, as someone who's currently getting back into skateboarding, I have to say that this game has won my heart. the flick-it mechanic and different controls for trick variations is just genius and it makes the entire experience so authentic for people into skateboarding. The first time I put this in the disk drive I played it for a little while and before I realized it 6 hours had passed.